The new item is also placed into the Windows clipboard,
ready to be pasted by other applications.

The format argument should be one of
(:text :rich-text :pixmap) and should correspond to
the type of object being placed onto the clipboard. Any object may be
passed with the :text format, in which case the
actual object is placed onto the lisp clipboard stack for pasting
within Lisp, while a string representation of the object is placed
onto the Windows clipboard for pasting into other applications. When
using the :rich-text format, the object must be a
string which is a valid piece of rich text, and when using the
:pixmap format the object must be a Common Graphics
pixmap, which is placed onto the Windows clipboard using the
"device-independent bitmap" format.

If a window or nil is passed as the
format, the function will act as if
:text were passed. (This behavior maintains
backward compatibility with pre-6.0 releases where the second argument
had to be a window or nil. The window was not
useful as an argument, while a format argument is.)

If empty-os-clipboard is true (as it is by
default), then the operating system is first cleared of objects of all
clipboard formats before adding the new object. This ensures that no
other objects are left on the OS clipboard with the new object. If
empty-os-clipboard is nil, then only the object of the specified format is
replaced on the OS clipboard.